Abstract:

A direct contact steam injection heater that includes a steam diffuser
having a plurality of steam diffusion holes that are selectively exposed
by a regulating member to control the amount of steam used to heat a
liquid. The regulating member is movable within the steam diffuser and
the steam diffuser includes a seating member to prevent the flow of steam
from the diffuser when the regulating member is in a completely closed,
seated position. At least one sealing members selectively exposes the
steam diffusion holes in the discharge region of the steam diffuser when
the regulating member moves between the open and closed positions. The
spacing of the steam diffusion holes along the steam diffuser can be
varied depending upon the desired resolution of the steam released as the
regulating member moves between its fully closed and fully open position.

Claims:

1. A direct contact steam injection heater comprising:a heater body having
a steam inlet, a liquid inlet, and a heated liquid outlet;a steam
diffuser positioned at the steam inlet to receive a flow of steam from
the steam inlet, the steam diffuser having a generally cylindrical outer
wall joined to an end wall;a discharge region formed in a portion of the
steam diffuser, the discharge region including a plurality of steam
diffusion holes through which steam is discharged from the steam
diffuser;a regulating member movably positioned within the steam diffuser
to control the discharge of steam from the discharge region, the
regulating member having an open interior defined by a cylindrical outer
wall extending between an open top end and an open bottom end that
includes a seating surface, wherein the open interior of the regulating
member receives the flow of steam; anda seating member positioned along
the end wall of the steam diffuser, wherein the seating surface on the
regulating member contacts the seating member to create an end seal to
prevent the flow of steam to the discharge region when the regulating
member is in a completely closed position.

2. The injection heater of claim 1 further comprising at least a first
sealing member extending around an outer surface of the regulating
member, the first sealing member being in contact with the outer wall of
the steam diffuser, wherein the first sealing member restricts the flow
of steam passing through the open bottom end of the regulating member
from reaching the steam diffusion holes in the discharge region.

3. The injection heater of claim 2 wherein the regulating member is
movable from the completely closed position to an open position, wherein
the first sealing member restricts the flow of steam between the outer
surface of the regulating member and the outer wall of the steam
diffuser.

4. The injection heater of claim 3 wherein the first sealing member is
positioned such that an increasing area of the discharge region is
exposed to the flow of steam as the regulating member moves from the
closed position to the open position.

5. The injection heater of claim 1 wherein the seating member is a
resilient ring received in a recessed receiving notch formed near the end
wall of the steam diffuser

6. The injection heater of claim 5 wherein the seating member is held
within the receiving notch by a retaining ring, wherein the retaining
ring is received within a recessed slot formed in the steam diffuser.

7. The injection heater of claim 2 further comprising a second sealing
member extending around the outer surface of the regulating member and
spaced from the first sealing member, wherein the discharge region is
positioned between the first sealing member and the second sealing member
when the regulating member is in the completely closed position.

8. The injection heater of claim 2 wherein the regulating member is a
piston positioned to receive the flow of steam at the open top end and
discharge the flow of steam through the open bottom end, wherein the
first sealing member is positioned around an outer circumference of the
piston, wherein the first flow seal exposes an increasing number of steam
diffusion holes in the discharge region to the flow of steam as the
piston moves from the closed position to the open position.

9. The injection heater of claim 1 wherein the plurality of steam
diffusion holes formed in the discharge region are formed in a pattern
extending from a lower end of the discharge region to an upper end of the
discharge region.

10. The injection heater of claim 9 wherein the plurality of steam
diffusion holes are evenly distributed along the pattern from the lower
end to the upper end of the discharge region.

11. The injection heater of claim 9 wherein the plurality of steam
diffusion holes are unevenly distributed along the pattern from the lower
end to the upper end of the discharge region

12. The injection heater of claim 9 wherein the pattern is a helical
pattern from the lower end to the upper end.

13. The injection heater of claim 12 wherein the plurality of steam
diffusion holes are evenly distributed along the helical pattern from the
lower end to the upper end of the discharge region.

14. The injection heater of claim 12 wherein the plurality of steam
diffusion holes are unevenly distributed along the helical pattern from
the lower end to the upper end of the discharge region.

15. A direct contact steam injection heater comprising:a heater body
having a steam inlet, a liquid inlet and a heated liquid outlet;a steam
diffuser positioned at the steam inlet to receive a flow of steam from
the steam inlet, the steam diffuser having a generally cylindrical outer
wall joined to an end wall;a discharge region formed in a portion of the
steam diffuser, the discharge region extending from a lower end to an
upper end, the discharge region including a plurality of steam diffusion
holes arranged in a pattern from the lower end to the upper end, wherein
steam is discharged from the steam diffuser through the pattern of steam
diffusion holes; anda regulating member movably positioned within the
steam diffuser, the regulating member having an open top end to receive
the flow of steam and an open bottom end to direct the flow of steam into
the steam diffuser,wherein the steam diffusion holes are unequally spaced
from each other along the pattern from the lower end to the upper end.

16. The injection heater of claim 15 wherein the steam diffusion holes are
more closely spaced near the lower end of the pattern than the upper end
of the pattern.

17. The injection heater of claim 15 wherein the steam diffusion holes are
more closely spaced near the upper end of the pattern than the lower end
of the pattern.

18. The injection heater of claim 16 wherein the pattern is a helical
pattern.

19. The injection heater of claim 17 wherein the pattern is a helical
pattern.

20. The injection heater of claim 15 further comprising at least a first
sealing member extending around an outer surface of the regulating member
and in contact with an inner surface of the outer wall of the steam
diffuser, wherein the first sealing member moves along the discharge
region when the regulating member is moved from the closed position to an
open position to selectively expose an increasing number of steam
diffuser holes.

21. The injection heater of claim 20 further comprising a seating member
positioned along the end wall of the steam diffuser, wherein the seating
member creates an end seal with a sealing surface formed on the open
bottom end of the regulating member.

22. The injection heater of claim 21 wherein the seating member is
received within a recess formed in the steam diffuser and is held in
place by a retaining ring.

Description:

CROSS-REFERENCE TO RELATED APPLICATION

[0001]The present application is based on and claims priority to U.S.
Provisional Patent Application Ser. No. 61/078,075 filed on Jul. 3, 2008.

BACKGROUND OF THE INVENTION

[0002]The present invention relates to direct contact steam injection
heaters. More specifically, the present invention relates to an
improvement for controlling the amount of steam flow into the liquid
being heated while also providing a liquid tight seal during a completely
closed condition.

[0003]In direct contact steam injection heaters, steam and/or any other
gaseous elements are directly mixed with a liquid being heated, or in
some cases with a slurry being heated. Direct contact steam injection
heaters are very effective at transferring heat energy from steam to the
liquid. The injection heater provides rapid heat transfer with virtually
no heat loss to atmosphere, and also transfers both the latent and the
available sensible heat of the steam to the liquid.

[0004]The present invention was developed during ongoing development
efforts by the assignee in the field of direct contact steam injection
heaters. U.S. Pat. Nos. 5,622,655; 5,842,497; 6,082,712; 6,361,025 and
7,152,851 all represent some of the prior art developments in direct
contact steam injection heaters by the assignee, and are hereby
incorporated by reference.

SUMMARY OF THE INVENTION

[0005]The present invention is a direct contact steam injection heater in
which steam is injected through a plurality of relatively small steam
diffusion holes in a steam diffuser into a liquid flowing through a
combining region in a heater body. The combining region has an inlet for
the liquid and an outlet for the heated liquid. The steam diffuser is
generally coaxial with and resides within the combining region. Steam
radially exits through the plurality of steam diffusion holes at a
generally sonic velocity into the liquid flow. The small radial jets of
steam into the axial flow of liquid within the combining region enhance
mixing of the liquid and steam.

[0006]The steam diffuser includes a discharge region having the plurality
of steam diffusion holes spaced in either an even or staggered pattern. A
regulating member is positioned within the steam diffuser to regulate the
amount of steam exiting the steam diffuser. Specifically, the regulating
member exposes an increasing number of the steam diffusion holes to the
flow of steam as the regulating member moves from a completely closed,
seated position to a fully open position.

[0007]The regulating member includes a lower, seating surface that
contacts a seating member formed as part of the steam diffuser. The
interaction between the seating member and the sealing surface of the
regulating member creates an end seal that prevents the flow of steam
past the seating member when the regulating member is in its completely
closed position. The regulating member may also include a first sealing
member and a second sealing member that are positioned on opposite sides
of the discharge region of the steam diffuser when the regulating member
is in its completely closed, seated position.

[0008]As the regulating member moves away from the completely closed,
seated position, the seating surface formed on the regulating member
moves out of contact with the seating member positioned along the bottom,
inside surface of the steam diffuser. Once the regulating member has
moved away from the seating member, steam is allowed to flow between the
regulating member and the outer wall of the steam diffuser, thereby
allowing steam to reach the discharge region and ultimately be discharged
through the plurality of steam diffusion holes. As the regulating member
moves away from the closed position, the first sealing member restricts
the flow of steam to control the amount of steam reaching the discharge
region when the regulating member is at its lower end of travel. As the
regulating member continues to move closer to the fully open position,
the first sealing member moves along the discharge region and exposes an
increasing number of the plurality of steam diffusion holes to the flow
of stream, thus increasing the amount of steam discharged from the
diffuser.

[0009]In one embodiment of the invention, the series of steam diffusion
holes formed in the steam diffuser are spaced from each other by a
constant distance along a helical path extending from the lower end of
the discharge region to an upper end of the discharge region. The equal
spacing between the steam diffusion holes in such an embodiment allows
for a constantly increasing number of the steam diffusion holes to be
exposed as the regulating member moves from the closed position to the
fully open position.

[0010]In an alternate embodiment, the steam diffusion holes can be
irregularly spaced from each other along the helical path defined in the
discharge region. In such embodiment, the steam diffusion holes can be
spaced closer together near the center of the helical path to provide
enhanced resolution as the regulating member exposes these holes during
its movement. Alternatively, the steam diffusion holes can be more
closely spaced either closer to the lower end of the discharge region or
closer to the upper end of the discharge region. In an embodiment in
which the steam diffusion holes are closely spaced near the lower end of
the discharge region, small movement of the regulating member away from
the fully closed position will provide enhanced resolution.
Alternatively, in an embodiment in which the steam diffusion holes are
closely spaced near the upper end of the discharge region, the regulating
member has enhanced resolution near the fully open position.

[0011]Other features and advantages of the invention will be apparent upon
inspecting the drawings and the following description thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012]The drawings illustrate the best mode presently contemplated of
carrying out the invention. In the drawings:

[0013]FIG. 1 is a perspective view of the direct contact steam injection
heater of the present invention;

[0014]FIG. 2 is a cross section view of the direct contact steam injection
heater of the present invention;

[0015]FIG. 3 is a side view of the steam diffuser illustrating the helical
pattern of the steam diffusion holes;

[0016]FIG. 4 is a side view of the steam diffuser illustrating the uneven
spacing of the steam diffusion holes along the discharge region of the
steam diffuser;

[0017]FIG. 5 is a magnified view showing the interaction between the
seating surface of the regulating member and the seating member
positioned along the bottom, inside surface of the steam diffuser;

[0018]FIG. 6 is a magnified view similar to FIG. 5 illustrating the
movement of the steam diffuser away from its fully closed position to a
partially open position; and

[0019]FIG. 7 is a magnified view similar to FIG. 6 illustrating the
position of the regulating member in a completely open position.

DETAILED DESCRIPTION OF THE INVENTION

[0020]FIG. 1 generally shows a direct contact steam injection heater 10
constructed in accordance with the present invention. The injection
heater 10 has a heater body 12 that includes a steam inlet 14, a liquid
inlet 16 and a heated liquid product discharge outlet 18. Steam flows
into the steam inlet 14 from a supply pipe 20. A liquid or slurry product
to be heated enters the heater body 12 through an inlet pipe 22 that is
coupled to the liquid inlet 16. As the liquid flows through the steam
injection heater 10, a flow of steam is injected into the liquid flow
such that the liquid flow is heated prior to exiting the heater body 12
at the heated liquid outlet 18.

[0021]As illustrated in FIG. 1, the steam injection heater 10 includes an
actuator 24 that controls the amount of steam injected into the liquid
flow in the manner to be described in greater detail below.

[0022]Referring now to FIG. 2, the steam inlet 14 is formed as a portion
of a steam housing 26. The steam housing 26 has a generally open interior
30 that defines a lower opening 32. As steam enters into the steam
housing 26, the flow of steam is directed toward the lower opening 32, as
illustrated by arrows 34.

[0023]The steam housing 26 includes an attachment flange 36 that is
positioned in contact with a similar attachment flange 38 formed as part
of the liquid housing 40.

[0024]As illustrated in FIG. 2, the liquid housing 40 includes the liquid
inlet 16. The flow of liquid, as represented by arrow 46, is directed
into a combining region 48 generally defined by the open interior of the
liquid housing 40. The combining region 48 is generally an open interior
of the heater body 12. In general, the combining region 48 is defined by
the generally cylindrical outer wall 50 and has an internal diameter
defined by the inner wall surface 52. The flow of liquid passes through
the combining region 48 and reaches the inwardly sloping lower wall 54
that directs the flow of fluid toward the heater liquid outlet 18.

[0025]A steam diffuser 58 is mounted across the upper opening 60 of the
liquid housing 40 in axial alignment with the lower opening 32 of the
steam housing 26. The steam diffuser 58 includes an outer wall 62
extending from an upper attachment flange 64. The attachment flange 64
includes a plurality of connectors 66 to secure the steam diffuser 58 to
an attachment surface 68 extending around the upper opening 60. The outer
wall 62 of the steam diffuser 58 is generally cylindrical and defines an
open interior 70. The open interior 70 extends from an open upper end 72
to an end wall 74. The end wall 74 is joined to the side wall 62 by an
angular wall 76.

[0026]The steam diffuser 58 includes a discharge region 78 formed in the
outer wall 62 slightly above the end wall 74. As can best be seen in FIG.
3, the discharge region 78 extends from a lower end 77 to an upper end 79
that are each generally illustrated by dashed lines in FIGS. 3 and 4. The
discharge region 78 includes a plurality of steam diffusion holes 80 that
each extend through the outer wall 62 to provide a flow passageway
between the open interior 70 of the steam diffuser 58 and the combining
region 48 such that steam can flow into the combining region 48 through
the steam diffusion holes 80, as illustrated by arrows 82 in FIG. 6.

[0027]As illustrated in FIG. 3, the steam diffusion holes 80 in the
discharge region 78 are arranged in a pattern. In the embodiment shown,
the steam diffusion holes 80 are arranged in a helical pattern. However,
other patterns are contemplated as being within the scope of the present
disclosure.

[0028]In the embodiment shown in FIG. 3, the steam diffusion holes 80 are
shown as equally spaced along the generally helical pattern from the
lower end 77 to the upper end 79. In the alternate embodiment of FIG. 4,
the steam diffusion holes 80 are unequally spaced along the helical
pattern. Specifically, in the embodiment of FIG. 4, as the steam
diffusion holes 80 get further away from the lowermost hole 81, the steam
diffusion holes 80 become more closely spaced until the steam diffusion
holes reach the uppermost steam diffusion hole 83. Alternatively, the
steam diffusion holes 80 could be more closely spaced at some other point
between the lower steam diffusion hole 81 and the upper steam diffusion
hole 83.

[0029]As illustrated in FIG. 3, the plurality of steam diffusion holes 80
are helically arranged along the outer wall 62. As will be described
below, the amount of steam supplied by the steam diffuser 58 into the
liquid flowing through the combining region 78 can be modulated by moving
a regulating member 84 to expose an increasing number of steam diffusion
holes 80.

[0030]Referring back to FIG. 2, steam injection heater 10 includes a
regulating member 84 removably positioned within the open interior 70 of
the steam diffuser 58. The regulating member 84 is movable along the
longitudinal axis of the steam diffuser 58 to selectively control the
amount of steam flow through the steam diffusion holes 80 in the
discharge region 78. The regulating member 84 is coupled to a actuation
stem 86 by a retaining pin 88. The actuation stem 86 passes through a top
opening 90 formed in the steam housing 26 and is coupled to the actuator
24 shown in FIG. 1. Packing material 92 surrounds the stem 86 and is held
in place by a packing nut 94. The packing material 92 in combination with
the packing nut 94 provide a seal around the actuator stem 86.

[0031]Referring now to FIGS. 6 and 7, the bottom end 100 of the regulating
member 84 includes a seating surface 106 that is recessed from the outer
wall 108. The seating surface 106 is recessed from the outer surface to
define shoulder 110.

[0032]As can also be seen in FIGS. 6 and 7, the end wall 74 of the steam
diffuser 58 includes a recessed, receiving notch 112. The receiving notch
112 receives an O-ring 114 and a seating member 116. The O-ring 114
formed from a resilient material and provides a counter force on the
seating member 116 when the seating surface 106 of the regulating member
84 is moved into contact with the seating member 116. Although the O-ring
114 is shown, other similar elements could be used to provide the counter
force on the seating member 116. The O-ring 114 and seating member 116
are held in place by a retaining ring 118 that in turn is received in a
recessed slot 119. In the embodiment of the invention shown in FIG. 6,
the seating member 116 is an angular member having a sloped contact
surface 120 that engages the seating surface 106 formed on the regulating
member 84, as shown in FIG. 5. In the preferred embodiment of the
invention, the seating member 116 is formed from brass, although other
materials are contemplated as being within the scope of the present
disclosure.

[0033]When the regulating member 84 is in its completely closed, seating
position, as shown in FIG. 5, the seating member 116 creates a fluid
tight end seal with the seating surface 106 that prevents the steam
within the open interior 104 from passing between the outer surface 108
of the regulating member 84 and the inner surface 122 of the outer wall
62. Thus, when the regulating member 84 is in its completely closed
position, the seating member 116 prevents the flow of steam from reaching
the steam diffusion holes 80 in the discharge region 78.

[0034]Referring back to FIG. 5, the regulating member 84 includes a first
sealing member 121 and a second sealing member 123. The first sealing
member is received within groove 124 recessed from the outer surface 108
and extends around the entire outer circumference of the regulating
member 84. The second sealing member 123 is received within a similar
groove 126. In the preferred embodiment of the invention, both the first
sealing member 121 and the second sealing member 123 are resilient,
annular rings that include a contact surface 128 that engages the inner
surface 122 of the outer wall 62. In the preferred embodiment of the
invention, both the first sealing member 121 and the second sealing
member 123 are components known as glyd rings. However, it is
contemplated that different components can be utilized for the first and
second sealing members 121, 123 while operating within the scope of the
present invention.

[0035]When the regulating member 84 is in its completely closed, seated
position, the first sealing member 121 is positioned below the discharge
region 78 while the second sealing member 123 is positioned above the
discharge region 78. Thus, the entire discharge region 78 is contained
between the first sealing member 121 and the second sealing member 123.
As described previously, when the regulating member 84 is in its
completely closed, seated position, the seating member 116 prevents the
flow of steam to the discharge region 78. When the regulating member 84
is fully seated, the first sealing member 121 and the second sealing
member 123 provide a controlling seal to prevent the liquid flowing
within the combining region 48 from entering into the steam diffuser past
the discharge region 78.

[0036]As the regulating member 84 is moved axially within the steam
diffuser, as shown in FIG. 6, the seating surface 106 of the regulating
member 84 is moved away from the sealing member 116 such that steam is
initially allowed to flow between the outer surface 108 of the regulating
member 84 and the inner surface 122 of the outer wall 62. The first
sealing member 121 functions as a controlling seal that allows controlled
leakage of steam past the sealing member 121. Since the sealing member
121 is continuously moved along the series of steam diffusion holes 80
within the discharge region 78, the first sealing member 121 cannot be
counted on to provide a liquid tight seal. Thus, the first sealing member
121 functions as a controlling member to allow a controlled leakage of
steam to the discharge region 78.

[0037]As the regulating member 84 continues to move upward as shown in
FIG. 7, the first sealing member 121 exposes an increasing number of the
steam diffusion holes 80. When the regulating member 84 reaches a
completely open position, the first sealing member 121 is positioned
above the discharge region 78 to expose all of the steam diffusion holes
80 contained within the discharge region 78, thereby allowing the maximum
amount of steam to reach the combining region 48.

[0038]As described previously, the first sealing member 121 allows a
controlled flow of steam once the seating surface 106 of the regulating
member 84 breaks contact with the sealing member 116. The first sealing
member 121 prevents excessive leakage past the seal. The controlled
leakage of steam past the first sealing member 121 is important such that
the amount of steam exiting the steam diffuser can closely track the
position of the regulating member in order to offer adequate steam
control. If the amount of steam leakage past the first sealing member 121
is excessive, too much steam will flow out of the discharge region 78 and
it may be impossible to control the temperature of the discharged liquid
at the lower end of the regulating member travel.

[0039]Referring now to FIGS. 3 and 4, as described previously, the spacing
between the individual steam diffusion holes 80 can be varied along a
helical pattern from the lower end 77 to the upper end 79, as best shown
in FIGS. 3 and 4. In the embodiment shown in FIG. 3, the steam diffusion
holes 80 are equally spaced from the lowermost steam diffusion holes 81
to the uppermost steam diffusion holes 83. In the embodiment shown in
FIG. 4, the steam diffusion holes 80 are more closely spaced in an upper
area between the lower steam diffusion hole 81 and the upper steam
diffusion hole 83. The tighter spacing between the steam diffusion holes
80 along the helical pattern increases the resolution of the system at
this location between the fully closed and fully open positions of the
regulating member.

[0040]Although one embodiment of the spacing between the steam diffusion
holes 80 is shown in FIG. 4, it should be understood that the spacing
between the steam diffusion holes 80 along the helical pattern shown
could be varied depending upon the system requirements. As an example,
when the steam diffusion holes 80 are more closely spaced near the
lowermost steam diffusion hole 81, the system provides for enhanced
resolution as the regulating member begins to initially open. Conversely,
when the steam diffusion holes are more closely spaced near the upper
steam diffusion hole 83, the system provides greater resolution near the
fully open position of the regulating member. It should be understood
that various different patterns of the steam diffusion holes 80 are
possible while operating within the scope of the present disclosure.

[0041]While the preferred embodiment of the invention has been shown in
connection with FIGS. 1-7, it should be noted that the invention is not
limited to this specific embodiment. For example, while the drawings show
a regulating member having a generally piston-like shape, it is
contemplated that the regulating member could have different shapes and
be movable in different manners to selectively expose a number of the
steam diffusion holes 80 within the discharge region 78.